1. Field of the Invention
Apparatuses and methods consistent with the invention relate to displaying three-dimensional images.
2. Description of the Related Art
Among methods of displaying three-dimensional images, a three-dimensional scanning method, a holography method, and a stereoscopy method are well known in the art. According to the holography method, an interference fringe is formed in a photosensitive material using a reference beam and an object beam that interfere with each other to form a three-dimensional image. When the reference beam is irradiated onto the three-dimensional image, the object beam is restored to display the three-dimensional image. According to the holography method, a coherent light source is required and it is difficult to record/reproduce a large object located far away. According to the stereoscopy method, two two-dimensional images having a binocular parallax are separately viewed by both eyes of a viewer, thereby making the image stereoscopic. According to the stereoscopic method, two plane images are used, and thus, it is easy to realize a three-dimensional image and to display the three-dimensional image having a high resolution. However, since the stereoscopy method only uses a horizontal parallax, it is difficult to realize a three-dimensional image having both a horizontal parallax and a vertical parallax.
On the other hand, according to the three-dimensional scanning method, a beam emitted by a light source is directly modulated in order to improve an optical efficiency and a contrast of the image. In a three-dimensional image displaying apparatus using the scanning method, the three-dimensional image can be displayed by scanning point beam in a three-dimensional manner or by scanning beam in x and y directions using a spatial light modulator and by moving a focus in a z direction. When the three-dimensional scanning method is performed using a two-dimensional spatial light modulator, the scanning can be performed at a high speed; however, fabrication costs increase. On the other hand, the point scanning method is inexpensive and requires simple equipment. Point scanning can be realized only when one-dimensional optical modulation can be performed in a propagating direction of the beam. However, it is difficult to realize one-dimensional optical modulation, and thus, point scanning cannot be widely used.